A liquid residual amount detection apparatus for a liquid container, includes: a sensor chamber that has a liquid supply port introducing liquid to be delivered from a liquid containing portion, and supplies the liquid to an external liquid consuming apparatus; a diaphragm that defines a part of the sensor chamber and is movable in response to a liquid containing amount in the sensor chamber; a pressure receiving plate that is attached to the diaphragm; a recess portion that is connected to the sensor chamber and is closed by the pressure receiving plate when the liquid containing amount in the sensor chamber becomes a predetermined amount or less; a piezoelectric element that applies vibration to at least a part of the recess portion so as to detect a free vibration state according to the applied vibration; a detection portion that detects an amplitude value or a frequency of a residual vibration waveform of a counter electromotive force by the free vibration state detected by the piezoelectric element; and a calculation portion that calculates a liquid residual amount in the liquid container on the basis of the amplitude value or the frequency of the residual vibration waveform detected by the detection portion.